Clouds are usually the most obvious feature of the sky.
They both reflect weather patterns and play a role in what the weather does.
The links below take you to a great deal of information about clouds.

Locations of clouds

Low-level clouds: (generally found
below 6,500 feet) Low-level clouds are usually composed of liquid water droplets,
but they can have snow and ice crystals in cold weather.

Mid-level clouds: (generally found
between 6,500 and 23,000 feet) Most mid-level clouds are composed of liquid
water droplets during summer and a liquid droplet-ice crystal mix during winter.
Mid-level cloud names are preceded by an "alto" prefix.

High-level clouds: (generally found above 20,000 feet)
High-level clouds are composed of ice crystals and tend to be very thin and
wispy. High-level cloud names are preceded by a "cirro" prefix.

Precipitation fog forms
when rain or snow falls.. As precipitation falls into drier air below the
cloud, the liquid drops or ice crystals evaporate or sublimate directly into
water vapor. The water vapor increases the moisture content of the air while
cooling the air. This often saturates the air below the cloud and allows fog
to form.

Upslope fog is very common
along large hills and mountains. It forms when winds blow up the side of a
hill or mountain, which cools the air.

Valley fog forms in mountain
valleys during winter and can be more than 1,500 feet thick. Often, the winter
sun is not strong enough to evaporate the fog during the day. When the air
cools again the following night, the fog often becomes thicker, which makes
it even harder for the sun to burn it off the following day. These fogs can
last for several days until strong winds blow the moist air out of the valley.
The tendency for cool, dense air to pool at the bottom of valleys also enhances
valley fog.